During motion of a planet from perihelion to aphelion, the work done b...
Answer:Work done by the gravitational force of the Sun on a planet
In order to determine whether the work done by the gravitational force of the Sun on a planet during its motion from perihelion to aphelion is positive, negative, zero, or may be positive or negative, we need to understand the concept of work and gravitational force.
Work
Work is defined as the transfer of energy that occurs when a force acts on an object, causing it to move in the direction of the force. Mathematically, work is given by the product of the force and the displacement of the object in the direction of the force.
Gravitational Force
The gravitational force is a force of attraction between two objects with mass, such as the Sun and a planet. It is always attractive and acts along the line joining the centers of the two objects. The magnitude of the gravitational force between two objects is given by Newton's law of universal gravitation.
Motion of a planet from perihelion to aphelion
Perihelion is the point in a planet's orbit where it is closest to the Sun, while aphelion is the point where it is farthest from the Sun. As the planet moves from perihelion to aphelion, the distance between the planet and the Sun increases.
Work done by the gravitational force of the Sun
The work done by the gravitational force of the Sun on a planet can be determined using the equation for work. However, in this case, the gravitational force is acting perpendicular to the displacement of the planet. Therefore, the work done by the gravitational force of the Sun on the planet is zero.
Explanation
When the gravitational force is acting perpendicular to the displacement, the angle between the force and displacement vectors is 90 degrees. In this case, the work done is given by the equation:
Work = Force * Displacement * cos(angle)
Since the angle is 90 degrees, the cosine of 90 degrees is zero. Therefore, the work done by the gravitational force of the Sun on the planet is zero.
Conclusion
The work done by the gravitational force of the Sun on a planet during its motion from perihelion to aphelion is zero.